Threaded connectors, such as a union comprising an internally threaded nut, for example, may be used to provide a preloaded threaded connection between two sections of pipe in a well servicing application. Such threaded connectors are commonly used for high pressure manifolding connections in well servicing applications, such as fracturing, stimulating, and cementing operations. Typically, the equipment, such as pumps, blenders, and threaded connectors, for example, that is required to rig up a manifolding network to a wellhead is transported to the wellsite. As the manifolding network is connected to the wellhead, two pipe sections may be coupled and a union with internal threads and external wings or lugs may be used to form a threaded connection with the two pipe sections by impact loading. First, a pin-end pipe section extends into a box-end pipe section with a face seal provided between them. Then the union is installed over the coupled pipe sections by internal threads on the union engaging external threads on one or both of the pipe sections to form the threaded connection. Finally, the threaded connection is preloaded to prevent the face seal from extruding under pressure. To preload the threaded connection, a sledge hammer is typically used to apply force to the radially extending lugs on the union, thereby rotating the union and tightening the threaded connection until a desired amount of preload force is achieved.
A significant amount of preload force may be required to maintain the face seal when under pressure. Hence, the impact load necessary to make up the threaded connection can be significant, requiring repeated blows of a sledge hammer that may weigh approximately 6 to 8 pounds, for example. Such impact loading may lead to various types of physical injuries, including stress-related injuries, to the personnel who make up these connections, especially in extremely cold or extremely hot environments.
Thus, a need exists for alternative apparatus and methods to make up threaded connections in well servicing applications without impact loading. The ability to make up threaded connections without impact loading may remove hazards associated with swinging hammers, trip hazards due to hydraulic and pneumatic lines and power tools, and flying debris from impact on traditional connections. Due to the significant preload force required in such threaded connections, the alternative apparatus and methods must be capable of applying the requisite preload force to maintain a positive face seal between two pipe sections when that threaded connection is under pressure.